As is generally well known, conventional vegetation mowing devices that are pulled behind a farm tractor or the like farm equipment, and that are powered by the Power Takeoff (PTO) shaft of such tractor employ mower decks that are made from metal and, more particularly, from steel that are painted in order to prevent steel oxidation that may eventually cause such metal mower deck to rust. However, as is well known, the paint is not effective in preventing rust due to the abuse seen by the mower deck during operation and storage. Thus, the user of such mowing devices is burdened by higher then desirable repair costs.
It is also common for such mower decks to encounter rigid objects, such as timbers, iron bars and the like that are disposed within the vegetation to be mowed and that are contacted by the rotating blade of the mowing device during operation. It is also common for such rigid objects to get wedged between the top surface of the blade and bottom surface of the mower deck and exert a greater than allowable force onto the gearbox. This high force causes the portion of the metal deck around the gearbox mounting holes to tear thus affecting the structural rigidity of the mower deck and rendering it inoperable without repair. The repair effort involves cutting gout a damaged portion and welding a plate that has the mounting hole pattern. When the structural damages are severe, the user is forced to purchase an entire mowing device as many manufacturers do not offer replacement mower decks. Thus, the user is further burdened by higher then desirable replacement costs.
Prior to the conception and development of the present invention, efforts have been made to alleviate disadvantages associated with use of metal mower decks. For example, U.S. Pat. No. 5,157,908 issued to Sebben et al. and U.S. Pat. No. 4,887,420 issued to Cerny, Jr. et al. disclose a mower deck for a riding lawn mover that is made entirely from thermoplastic material. In another example, U.S. Pat. No. 5,638,668 issued to Kallevig et al. teaches a plastic liner for a metal deck.
However, applicant is not aware of plastic decks that are designed to withstand operational rigors of mowing devices pulled behind a farm tractor and that reduce maintenance and replacement costs of such devices due to encounters with rigid objects. Thus, there is a need for the polymer mower decks for mowing devices pulled behind the farm tractor that reduce maintenance and repair costs associated with operational environment.